Thanks Jan.

I am not sure whether this is in the feature pipeline.

Another related query, *Live/Push queries* on views, the idea is to have a
pub/sub kind of model, where clients subscribe to queries / views.



On Wed, Nov 30, 2016 at 4:53 AM, Jan Lehnardt <[email protected]> wrote:

>
> > On 30 Nov 2016, at 00:06, Alan Kash <[email protected]> wrote:
> >
> > Yes, from the link it mentions about stale views.
> >
> > Will be interested to know the merits of db pool vs view pool first
> model.
> > Logically, the queries are coming from top, and the view updates are
> > propagated bottom up.
>
> The internal data structure benefits from bulk inserts vs single inserts.
>
> I.e. it takes (accumulated) less CPU, RAM, Disk, to update the view index
> with 10 docs in one bulk operation instead of 10 individual operations.
>
> > On a similar note, do the view updates leverage
> > parallel processing in multicore systems.
>
> In CouchDB 1.x: no, this is single threaded, albeit spread over two
> operating system processes, but using a blocking protocol, so together,
> they wouldn’t exhaust a single CPU.
>
> In CouchDB 2.x, if you set up multiple shards per cluster node, you
> basically get a CPU per shard for view computation, effectively using
> multicore systems optimally.
>
> Best
> Jan
> --
>
>
> >
> >
> >
> > On Tue, Nov 29, 2016 at 5:49 PM, Robert Keizer <[email protected]> wrote:
> >
> >> After a document is added.
> >>
> >> My understanding is that the insertion to the main document pool happens
> >> at the start, with views being triggered to update after the document
> >> exists in that index.
> >>
> >> Someone with more experience may correct me - but I'm fairly certain
> >> this is why views can be stale (
> >> http://docs.couchdb.org/en/2.0.0/api/ddoc/views.html )
> >>
> >>
> >> On 2016-11-29 4:47 PM, Alan Kash wrote:
> >>> Hello,
> >>>
> >>> CouchDB starter here.
> >>>
> >>> How are the MapReduce views updated ? Before or after a new document is
> >>> added into store ?
> >>>
> >>> Do all document insertions go through some view process pipeline, then
> >>> finally to base document pool ?  I am thinking in document stream
> >>> processing terms, where document ingress hits the *views processes*
> first
> >>> before finally ending up in the pool.
> >>>
> >>> Thanks
> >>>
> >>
> >>
> >>
>
> --
> Professional Support for Apache CouchDB:
> https://neighbourhood.ie/couchdb-support/
>
>

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